1. Field of the Invention
This invention relates to an improved jack for data transmission, and in the preferred embodiment provides a jack having improved cross-talk characteristics.
2. The Prior Art
Jacks (and their associated plugs) are widely used in data transmission systems for providing a plug-in connection between components. For example, jacks are extensively used on patch panels and wall outlets of structured cabling systems and on electronic equipment to permit connection of equipment to structured cabling systems using patch leads. The so called RJ45 plug is extensively used within the cabling industry and the vast majority of jacks are devised to be compatible with RJ45 plugs.
There are various internationally agreed standards for the performance of structured cabling systems. The current mainstream standards are the so called “Category 5” (commonly referred to as Cat 5) and the somewhat improved “Category 5 enhanced” (generally referred to as Cat 5e). A higher standard (Category 6 or Cat 6) has recently been proposed. Cat 6 specifications require lower levels of near end cross-talk (NEXT) and far end cross-talk (FEXT) and improved return loss values than the earlier Cat 5 and Cat 5e standards. In order to meet Cat 6standards it has been necessary to re-design both plugs and jacks, whilst keeping within the physical parameters of the RJ45 plug specification.
By careful design of the plug and the circuit board to which the jack is secured it has been possible to design plug and jack combinations which meet Cat 6 standards without any fundamental alteration to the standard jack construction. However, it is now considered desirable that both the plug and jack of Cat 6 specification equipment must be capable of meeting Cat 5 specification when used with a mating Cat 5 component. In other words, it is now desirable that when a Cat 6 plug is inserted into a Cat 5 jack, or a Cat 5 plug is inserted in a Cat 6 jack, the overall combination should meet Cat 5 standards.
We have now devised an improved jack which assists in meeting the desideratum of rearward compatibility to Cat 5 standards.